The Early Cretaceous Sembar Shale Formation, situated in Pakistan's southern Indus Basin, is regarded as one of the most promising yet unexplored shale units for unconventional hydrocarbon resources. Despite its geological potential, detailed studies that integrate geochemical, mineralogical, and basin modeling approaches have been limited. This study aims to evaluate the oil and gas generation potential of the Sembar Shale using a multidisciplinary dataset from three exploration wells. Petrographic observations, Rock–Eval pyrolysis, vitrinite reflectance measurements, Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and 1-D basin modeling were employed to characterize the source rock properties and thermal maturity. The shale samples exhibited total organic carbon (TOC) values ranging from 0.76 to 3.07 wt%, with a Hydrogen Index (HI) up to 463 mg HC/g TOC, suggesting significant potential for both oil and gas generation. Vitrinite reflectance (VRo) values of 0.56% to 1.23% indicate a thermal maturity range from the early oil to the wet gas window. SEM–EDS and FTIR analyses revealed a high abundance of authigenic micro-quartz, along with fabric and non-fabric pore types that enhance reservoir quality. Basin modeling confirmed that the Sembar Formation entered the gas generation phase from the Early Oligocene to the present day, especially at greater burial depths, with transformation ratios (TR) as high as 94%. These findings suggest that the formation possesses the geochemical and mechanical attributes of a viable unconventional reservoir, warranting further exploration and development. However, additional economic assessments and production testing are necessary to evaluate commercial viability. This integrated approach provides a robust framework for mitigating exploration risk in shale plays in comparable frontier basins.